Mononuclear and dinuclear bromide-nitrite cadmium(II) complexes with related 1,4-diazabicyclo[2.2.2]octane ligands

Bicyclic ammonium ionic liquids as dense hypergolic fuels

1-Aza-bicyclo[2.2.2]octane/1,4-diazabicyclo[2.2.2]octane-based dicyanamide possesses higher densities (1.06–1.31 cm⁻³) than the corresponding pyrrolidinium and imidazolium-based isomers, besides hypergolicity with white fuming nitric acid.

Crystal structure of di-μ2-chlorido-bis-[(1-aza-4-azoniabi-cyclo-[2.2.2]octane-κN (1))di-chlorido-dicadmium]

In the structure of the binuclear title compound, [Cd₂(C₆H₁₃N₂)₂Cl₆], two Cd^II atoms are bridged by two Cl⁻ ligands, defining a centrosymmetric Cd₂Cl₂ motif. Each metal cation is additionally coordinated by two Cl⁻ ligands and the N atom of a protonated 1,4-di­aza­bicyclo­[2.2.2]octane (H-DABCO)⁺ ligand, leading to an overall trigonal–bipyramidal coordination environment with one of the bridging Cl⁻ ligands and the N atom at the apical sites. In the crystal, the neutral dimers are linked via N—H⋯Cl hydrogen bonds, forming a two-dimensional network expanding parallel to (100).

A novel cadmium(II) coordination polymer containing two kinds of independent one-dimensional chain

The structure of the title compound, catena-poly[[cadmium(II)-di-μ-chlorido-μ-(1,4-diazoniabicyclo[2.2.2]octane-1-carboxylato)] [[aquachloridocadmium(II)]-di-μ-chlorido] dihydrate], {[Cd(C₈H₁₅N₂O₂)Cl₂][CdCl₃(H₂O)]·2H₂O}n, contains two kinds of independent one-dimensional chain, viz. {[Cd(C₈H₁₅N₂O₂)Cl₂]⁺}n and {[CdCl₃(H₂O)]⁻}n, and uncoordinated water molecules. Each CdII cation in the {[Cd(C₈H₁₅N₂O₂)Cl₂]⁺}n chain is octahedrally coordinated by two pairs of bridging chloride ligands and two O atoms from different bridging carboxylate groups. CdII cations in the {[CdCl₃(H₂O)]⁻}n chain are also octahedrally surrounded by four bridging chloride ligands, one terminal chloride ligand and one coordinated water molecule. Hydrogen bonds between solvent water molecules and these two independent chains generate a three-dimensional framework containing two-dimensional zigzag layers.

catena-Poly[1,4-dihydroxy-1,4-diazoniabicyclo[2.2.2]octane [aquatri-μ-chlorido-trichloridodicuprate(II)]]

The title compound, {(C6H14N2O2)[Cu2Cl6(H2O)]}n, consists of 1,4-dihydroxy-1,4-diazoniabicyclo[2.2.2]octane dications and one-dimensional inorganic anionic {[Cu2Cl6(H2O)](2-)}n chains in which both five-coordinate [CuCl3(H2O)](-) and five-coordinate [CuCl3](-) units exist. These two distinct type of unit are linked together by one chloride ion and are bridged across centres of inversion to further units of their own type through two chloride ions, giving rise to novel polymeric zigzag chains parallel to the c axis. The chains are connected by O-H···Cl hydrogen bonds to produce R2(4)(16) ring motifs, resulting in two-dimensional layers parallel to the ac plane. These layers are linked into a three-dimensional framework with the organic cations via O-H···Cl hydrogen bonds. Hydrogen bonding between the chains, and between the chains and the organic cations, provides stability to the crystal structure.